Low variability of single-molecule conductance assisted by bulky metal–molecule contacts

Ferradas, Ruben R. ; Marques-Gonzalez, Santiago ; Osorio, Henrry M. ; Ferrer, Jaime ; Cea, Pilar (Universidad de Zaragoza) ; Milan, David C. ; Vezzoli, Andrea ; Higgins, Simon J. ; Nichols, Richard J. ; Low, Paul J. ; Garcia-Suarez, Victor M. ; Martin, Santiago (Universidad de Zaragoza)

Resumen: A detailed study of the trimethylsilylethynyl moiety, –C[triple bond, length as m-dash]CSiMe3 (TMSE), as an anchoring group in metal|molecule|metal junctions, using a combination of experiment and density functional theory is presented. It is shown that the TMSE anchoring group provides improved control over the molecule–substrate arrangement within metal|molecule|metal junctions, with the steric bulk of the methyl groups limiting the number of highly transmissive binding sites at the electrode surface, resulting in a single sharp peak in the conductance histograms recorded by both the in situ break junction and I(s) STM techniques. As a consequence of the low accessibility of the TMSE group to surface binding configurations of measurable conductance, only about 10% of gold break junction formation cycles result in the clear formation of molecular junctions in the experimental histograms. The DFT-computed transmission characteristics of junctions formed from the TMSE-contacted oligo(phenylene)ethynylene (OPE)-based molecules described here are dominated by tunneling effects through the highest-occupied molecular orbitals (HOMOs). This gives rise to similar conductance characteristics in these TMSE-contacted systems as found in low conductance-type junctions based on comparably structured OPE-derivatives with amine-contacts that also conduct through HOMO-based channels.

Idioma: Inglés

DOI: 10.1039/c6ra15477h

Año: 2016

Publicado en: RSC Advances 6, 79 (2016), 75111-75121
ISSN: 2046-2069

Factor impacto JCR: 3.108 (2016)

Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 59 / 166 = 0.355 (2016) - Q2 - T2

Factor impacto SCIMAGO: 0.889 - Chemistry (miscellaneous) (Q1) - Chemical Engineering (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E54
Financiación: info:eu-repo/grantAgreement/ES/MINECO/CTQ2012-33198
Financiación: info:eu-repo/grantAgreement/ES/MINECO/CTQ2012-50187-EXP
Financiación: info:eu-repo/grantAgreement/ES/MINECO/FIS2012-34858
Financiación: info:eu-repo/grantAgreement/ES/MINECO/RYC-2010-06053

Tipo y forma: Article (Published version)

Área (Departamento): Área Química Física (Dpto. Química Física)